QuEChERS-超高效液相色谱-串联质谱法测定果蔬中螺虫乙酯、丁醚脲及代谢物残留

建立了QuEChERS前处理-超高效液相色谱-串联质谱 (UPLC-MS/MS) 测定果蔬中螺虫乙酯、丁醚脲及其6种代谢物 (螺虫乙酯-烯醇、螺虫乙酯-烯醇-糖苷、螺虫乙酯-单羟基、螺虫乙酯-酮-羟基、丁醚脲-脲和丁醚脲-甲酰胺) 残留量的分析方法。样品经破壁机匀浆，V(乙腈) : V(甲酸)=10 : 1混合溶液涡旋提取，定制的QuEChERS净化管净化，岛津Shim-pack XR-ODS色谱柱分离 (75 mm × 2.0 mm，1.6 μm)。采用电喷雾离子源正离子多反应监测模式进行质谱检测，外标法定量。丁醚脲-脲和丁醚脲-甲酰胺在0.001~0.1 mg/L范围内线性关系良好，其他6种化合物在0.005~0.5 mg/L范围内线性关系良好，R2 ≥ 0.999 3。验证了梨、葡萄、西瓜、芥蓝、芹菜和韭菜6种基质下方法的准确度和精密度，在0.001~0.5 mg/kg添加水平下，8种化合物的平均回收率在68%~94%之间，相对标准偏差在5.4%~15%之间，定量限为0.001~0.005 mg/kg。该方法简便、快速、可靠，适用于同时测定果蔬中上述8种化合物残留。

Residue of spirotetramat, diafenthiuron and their metabolites in fruits and vegetables by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry

A method was developed for the quantitative determination of spirotetramat, diafenthiuron and their metabolite residues (spirotetramat-enol, spirotetramat-enol-glucoside, spirotetramat-mono-hydroxy, spriotetramat-keto-hydroxy, diafenthiuron-urea, diafenthiuron-amide) by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were homogenized, extracted with V (acetonitrile) : V(formic acid)=10 : 1, and cleaned-up by custom QuEChERS tubes. The separation was performed on a Shimadu Shim-pack XR-ODS column(75 mm × 2.0 mm, 1.6 μm). The compounds were identified by MS/MS in positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) mode, and quantified by external standard method. The linearities of diafenthiuron-urea and diafenthiuron-amide ranged from 0.001 to 0.1 mg/L. And that of the other six compounds ranged from 0.005 to 0.5 mg/L, with the correlation coeffecients higher than 0.999 3. At the fortified level from 0.001 mg/kg to 0.5 mg/kg in pear, grape, watermelon, kale, celery and leek, the average recoveries of all the eight compounds ranged from 68% to 94% with the relative standard deviations varied from 5.4% to 15%. The limits of quantification (LOQ) of the analytes were 0.001-0.005 mg/kg. The method is simple, rapid, accurate and suitable for the confirmation and quantification of those eight compounds in fruits and vegetables.